Molecular Belts and Collars in the Making: A Hexaepoxyoctacosahydro[12]cyclacene Derivative

Kohnke, Franz H.; Slawin, Alexandra M. Z.; Williams, David J.

doi:10.1002/anie.198708921

Cited by 162 publications

(84 citation statements)

References 17 publications

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“…There have been reports of the systems in which -orbitals are oriented vertically to the plane of the rings, namely belt-shape carbocyclic-conjugated systems (such as annulenes, beltenes, cyclacenes, and collarenes) (28)(29)(30)(31)(32)(33)(34)(35)(36)(37). The recent discoveries of fully conjugated systems with a curved surface like fullerenes and carbon nanotubes (38,39) further adds fuel to such a kind of study.…”

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Ionophores and receptors using cation-π interactions: Collarenes

Choi

Suh

Cho

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

153

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Cation-interactions are important forces in molecular recognition by biological receptors, enzyme catalysis, and crystal engineering. We have harnessed these interactions in designing molecular systems with circular arrangement of benzene units that are capable of acting as ionophores and models for biological receptors.[n]Collarenes are promising candidates with high selectivity for a specific cation, depending on n, because of their structural rigidity and well-defined cavity size. [12]Collarene exhibits a pronounced affinity for tetramethylammonium cation and acetylcholine, which implies that it could serve as a model for acetylcholinestrase. Thus, collarenes can prove to be novel and effective ionophores͞model-receptors capable of heralding a new direction in molecular recognition and host-guest chemistry.The design of novel ionophores and receptors has attracted considerable interest in the recent past (1-5). The cationinteraction discovered by Dougherty and coworkers (6, 7) has received much attention as a new type of binding force important in biological molecular recognition (8-15), enzyme catalysis (16, 17), and crystal engineering (3, 18). This cationinteraction is known to be responsible for the binding of acetylcholine (ACh) to its deactivating enzyme (8, 9), acetylcholinestrase (19,20), which has served as a target receptor in designing therapeutic agents against various ailments like myasthenia gravis, glaucoma, and Alzheimer's disease (21-23).A lot of effort and concern has been evinced on the disposal of nuclear wastes. A major bottleneck, however, stems from the effective separation of major hazardous isotopes (such as 137 Cs and 90 Sr, which have fairly long half-lives of Ϸ30 years) from these wastes (24-27). There have been extensive attempts to design and develop systems that can be used in nuclear waste separations as effective ionophores. In this context the use of various types of ionophores has been reported (25-27), and there have been extensive attempts to explore new types of ionophores that have a high selectivity for these hazardous isotopes.It therefore is appealing to investigate the possibility of designing novel ionophores and model receptors based on the principle of the cation-interaction. There have been reports of the systems in which -orbitals are oriented vertically to the plane of the rings, namely belt-shape carbocyclic-conjugated systems (such as annulenes, beltenes, cyclacenes, and collarenes) (28-37). The recent discoveries of fully conjugated systems with a curved surface like fullerenes and carbon nanotubes (38, 39) further adds fuel to such a kind of study. However, belt-shape carbocyclic-conjugated systems have hardly been studied apart from the synthetic study of cyclacene precursors and collarenes (32-37).Thus, it would be of importance to investigate whether cyclacenes (comprised of only benzene moieties) and collarenes (having CH 2 linkages between benzene units) can behave as ionophores and receptors. These molecular structures can be understood f...

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“…The recent discoveries of fully conjugated systems with a curved surface like fullerenes and carbon nanotubes (38,39) further adds fuel to such a kind of study. However, belt-shape carbocyclic-conjugated systems have hardly been studied apart from the synthetic study of cyclacene precursors and collarenes (32)(33)(34)(35)(36)(37).…”

mentioning

confidence: 99%

Ionophores and receptors using cation-π interactions: Collarenes

Choi

Suh

Cho

et al. 1998

Proc. Natl. Acad. Sci. U.S.A.

153

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“…Our current interest (Kohnke, Slawin, Stoddart & Williams, 1987;Ellwood, Mathias, Stoddart & Kohnke, 1988;Stoddart, 1988aStoddart, ,b, 1989 Kohnke & Stoddart, 1989) in the use of repetitive Diels-Alder reactions (Thomas & Miller, 1986;Chiba, Kenny & Millar, 1987) to yield polyacene and cyclacene derivatives has led us to identify syn-2, 3,6,7-tetrakis(chloromethyl)-1,4: 5,8-diepoxy-1,2,-3,4,5,6,7,8-octahydroanthracene (3) and its anti isomer (4) as immediate precursors (see scheme) to the corresponding bisdienes (5) and (6). The tetrachlorides (3) and (4) can be obtained (Luo & Hart, 1988) (3) and (4)] can be separated (see Experimental) by silica gel chromatography, their relative configurations cannot be assigned unambiguously by NMR (1H or 13C) spectroscopies.…”

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rel-(1R,2S,3R,4S,5S,6R,7S,8R)-2,3,6,7-Tetrakis(chloromethyl)-1,4:5,8-diepoxy-1,2,3,4,5,6,7,8-octahydroanthracene

Kohnke¹,

Mathias²,

Stoddart³

et al. 1990

Acta Crystallogr C

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“…In the course of the synthesis (Kohnke, Slawin, Stoddart & Williams, 1987) of a new class of rigid macropolycyclic molecules with belt-like shapes that relies upon the Diels-Alder reaction, the bisdiene (1) (Vogel & Florey, 1974) was identified as one of the key starting materials. It can be prepared (Mahaim, Carrupt, Hagenbuch, Florey & Vogel, 1980) in four steps from the exo-furan-maleic anhydride adduct which is subjected, in the first instance, to catalytic carbonylation (James & Stille, 1976) in methanolic solution to afford a tetraester.…”

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confidence: 99%

“…On basis of the 1H and Iac NMR spectroscopic data, this compound has been assigned (Mahaim et al, 1980) the all-exo configuration (2). During our own preparation of a sample of the bisdiene (1), good-quality single crystals were obtained (Kohnke et al, 1987 …”

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confidence: 99%